The limit on the number of LXs is 2048. Some of the LXs are reserved as system LXs; the rest are available as non-system LXs. You can use the NSYSLX parameter in the IEASYSxx member of SYS1.PARMLIB to set the number of system LXs available for the system's use. Use the LXRES macro with SYSTEM=YES to obtain a system LX; with SYSTEM=NO to obtain a non-system LX. The rule for the reuse of a system LX is simple: the system does not reassign it. The original requester of the LX can choose to reconnect to the LX should the address space terminate and then restart. The system considers reusing a non-system LX when all entry tables are disconnected from the LX. This is the case when:

• an address space that owns a non-system LX terminates or when the owner of the non-system LX uses ETDIS to disconnect all entry tables the entry table from the LX and uses LXFRE to free the LX; and
• all address spaces that have used ETCON to connect the LX to that entry table have either terminated or used ETDIS to disconnect the entry table from the LX.